2 Specification

3 Description

E04WFF may be used to supply values for optional parameters to
E04WDF. It is only necessary to call E04WFF for those parameters whose values are to be different from their default values. One call to E04WFF sets one parameter value.

Each optional parameter is defined by a single character string,
of up to 72 characters,
consisting of one or more items. The items associated with a given option must be separated by spaces, or equals signs =. Alphabetic characters may be upper or lower case. The string

Print Level = 1

is an example of a string used to set an optional parameter. For each option the string contains one or more of the following items:

–

a mandatory keyword;

–

a phrase that qualifies the keyword;

–

a number that specifies an integer or real value. Such numbers may be up to 16 contiguous characters
in Fortran's I, F, E or D formats,
terminated by a space if this is not the last item on the line.

For E04WFF, each user-specified option is not normally printed as it is defined, but this printing may be turned on using the keyword List. Thus the statement

CALL E04WFF ('List', IW, RW, IFAIL)

turns on printing of this and subsequent options. Printing may be turned off again using the keyword Nolist.

Optional parameter settings are preserved following a call to E04WDF and so the keyword Defaults is provided to allow you to reset all the optional parameters to their default values before a subsequent call to E04WDF.

A complete list of optional parameters, their abbreviations, synonyms and default values is given in Section 11 in E04WDF.

4 References

5 Parameters

Note: the dimension of the array IW
must be at least
LENIW (see E04WCF).

3: RW(*) – REAL (KIND=nag_wp) arrayCommunication Array

Note: the dimension of the array RW
must be at least
LENRW (see E04WCF).

4: IFAIL – INTEGERInput/Output

On entry: IFAIL must be set to 0, -1​ or ​1. If you are unfamiliar with this parameter you should refer to Section 3.3 in the Essential Introduction for details.

For environments where it might be inappropriate to halt program execution when an error is detected, the value -1​ or ​1 is recommended. If the output of error messages is undesirable, then the value 1 is recommended. Otherwise, if you are not familiar with this parameter, the recommended value is 0. When the value -1​ or ​1 is used it is essential to test the value of IFAIL on exit.

On exit: IFAIL=0 unless the routine detects an error or a warning has been flagged (see Section 6).

6 Error Indicators and Warnings

If on entry IFAIL=0 or -1, explanatory error messages are output on the current error message unit (as defined by X04AAF).